This invention relates to an optical fiber alignment element structure that employs integrated micro ball lens and particularly a structure that adapts lithography, patternetching and micro machining techniques to fabricate optical elements by forming V-shaped grooves or waveguides and micro ball lenses in batch, then integrate the V-shaped grooves, waveguides and micro ball lenses for completing optical path control of the optical fiber passive elements.
In optical fiber communication, there are a number of techniques being adapted for the alignment of optical fiber passive elements. One is the fused biconical taper technique which aligns two optical fibers directly, then fuses the aligned fibers and stretches the fibers to connect the fiber cores at two ends together under the polymerization force effect. The connection made by this technique tends to cause power loss because the diameters of the coupling optical fibers could be not equal, the alignment of the fibers not precise, or the surfaces of the fiber connection ends not even and smooth.
Another technique is to dispose a gradient index lens (GRIN lens) at one end of an optical fiber for channeling optical signals of the fiber to the GRIN lens. The photo signals are amplified and paralleled to focus on another optical fiber. This technique costs higher and needs human labor to do micro assembly. There is yet another technique which forms a microlens at the end of each optical fiber for converging and focusing light between the coupled fibers to transmit optical signals. This method requires process for every fiber end. Still another technique is to dispose a ball lens between two optical fibers or waveguides. The ball lens focuses light received from a fiber at one side and transmits photo signals to another fiber at another side. The ball lens being used is ground by high precision ceramic means. The fabrication process is complex. Furthermore, the techniques of using GRIN lens or ball lens need human labor to micro assemble the GRIN lens at the end of the optical fibers, or to dispose the ball lens between the coupling fibers. Each pair of coupling fibers needs a GRIN lens or ball lens. They take a lot of process time and cannot be produced in batch. When micro assemble the ball lens between the optical fibers by human labor, it is prone to produce alignment deviation between the fiber center line and ball lens center, and might result in loss of optical signal transmission power. There is still another method which employs surface micro machining technique to produce a lens vertically positioned between the coupling optical fibers. However this method has a higher cost and a more complicated fabrication process.
It is therefore an object of this invention to provide an improved optical fiber alignment element to resolve aforesaid problems and disadvantages. This invention forms a plurality of V-shaped grooves, wavegiudes and micro ball lens on a substrate such that the optical fibers or waveguides may be precisely aligned with the micro ball lenses without human labor micro assembly of the micro ball lenses between the optical fibers or waveguides.
Another object of this invention is to employ lithography and patternetching techniques and heating process to form the waveguides, micro ball lens and V-shaped grooves on the surface of the substrate whereby to increase accuracy of alignment between the micro ball lenses and optical fibers or waveguides.
A further object of this invention is to provide a simpler fabrication method to improve manufacturing process.
Yet another object of this invention is to fabricate V-shaped grooves, waveguides and micro ball lenses on a substrate by integrated and batch processes for increasing total production efficiency.
In order to achieve aforesaid objects, this invention includes etching a plurality of V-shaped grooves or micro machining a plurality of waveguides on a substrate surface in an array manner; coating a first polymer layer and a high transparency second polymer layer on the substrate surface; placing the substrate through a lithography process and heating process to form a plurality of base pads and spherical micro ball lenses at selected locations of the substrate surface; disposing optical fibers in the V-shaped grooves; and encasing an upper cap over the micro ball lens and optical fibers or waveguides. Through the foregoing processes, the micro ball lenses and V-shaped grooves or waveguides may be positioned at selected locations for the optical fibers located at two sides of the micro ball lenses to align precisely. The process is simpler, more precise, and may produce the optical fiber alignment element in an integrated and batch fashion.